1. Field of the Invention
The present invention relates to a device for the uniform application of gas on a plane surface.
A particularly uniform application of gas on a surface is of great importance whenever heat is to be transferred to an article by means of this flowing gas, since only then a uniform heat transfer or possibly also material exchange between gas flow and surface is guaranteed, without any major differences in the local heat transfer coefficient leading to different temperatures and/or different heating of the article. This poses a great problem, for instance, in the warming of metal bobbins or spools. These are understood to be metal sheets, for instance, aluminum sheets wound to form a cylinder.
For the purpose of decreasing the annealing time one object is to increase as much as possible the heat transfer in a chamber furnace, as used for instance in the aluminum industry for the annealing of sheet bobbins or spools. If the blowing system used results in large local differences in the heat transfer, local warming may occur which causes discoloring of the metal sheets and moreover can impair the desired metallurgical properties of the sheets.
2. Description of the Prior Art
Conventional blowing systems which have a high heat transfer, have nozzles in the form of holes or slots which produce impact jets perpendicularly impinging on the front face of the metal bobbins or spools. If local overheating is determined, very often there is no choice but to reduce the overall volume flow and thus avoid the high local heat transfer coefficients.